Apparatus for the combustion of fuel, including a tubular walled combustion chamber



06L 1951 c. A. BONVILLIAN ETAL 2,569,446

APPARATUS FOR THE coususnou 0F FUEL, mcwnmc A TUBULAR WALLED COMBUSTIONCHAMBER Filed Oct. 18, 1943 4 Sheets-Sheet 1 3o 2g 20 I 24 c1 2a 25 v 25l9 FIG. 2

WITNESSES.

. c. A. BONVILLIAN ETAL APPARATUS FOR THE coususrrxou OF FUEL, INCLUDINGOct. 2; 1951 A TUBULAR HAL-LED COMBUSTION CHAMBER 4 Sheets-Sheet 2 FiledOct. 18, 1943 WITBESSES -83&wnu9 /A w\ M44 1951 c. A. BONVILLIAN EI'AL2,569,446

APPARATUS FOR THE COMBUSTION 0F FUEL, INCLUDING A TUBULAR WALLEDCOMBUSTION CHAMBER Filed Oct. 18, 1943 4 Sheets-Sheet 5 WIT NESSES.INVENTORS.

1951 c. A. BONVILLIAN EI'AL ,569,

APPARATUS FOR THE coususnon OF FUEL, mcwomc A TUBULAR WALL-ED COMBUSTIONCHAMBER Filed on. 1a, 1943 4 Sheets-Sheet 4 FIG 7 INVENTORS. M I w I,Patented Oct. .2, 1951 APPARATUS FOR THE COMBUSTION FUEL, INCLUDING ATUBULAR WALLED COMBUSTION CHAMBER Claude A. Bonvillian, Wynnewood, RalphC.

Brierly, Narberth, and Samuel Letvin, Philadelphia, Pa.

Application October 18, 1943, Serial No. 506,870

4 Claims.

(Cl. Bil-39.32)

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) This invention relates to thecombustion of fuels.

This application is related to our application Serial No. 479,010, flledMarch 13, 1943, issued March 21, 1950 as Patent No. 2,500,925, forMethod and Apparatus for the Combustion of Fuel, in that thisapplication discloses other forms of the inventions disclosed in thatapplication.

The invention provides novel apparatus for the combustion of fuels,preferably at relatively high heat releases, which are applicable to awide vari:- ety of uses, such as gas turbine systems, vapor generators,vapor superheaters, the heating of fluids, and the rocket or jetpropulsion of aircraft. The apparatus of the present invention ischaracterized more particularly by the provision of a combustion chamberhaving a tubular wall of improved construction.

Furnaces embodying the invention preferably have an outer casing andmeans forming a combustion chamber within, and in spaced relationshipto, the outer casing so arranged that secondary air may be supplied tothe region surrounding the combustion chamber and delivered therefrom tothe chamber to support combustion therein. The outer casing or the meansforming the combustion chamber, or both, in the forms of the inventiondisclosed herein, include tubular members through which a suitablecoolant is passed. Some or all of the coolant in the tubular members maybe delivered into direct contact with the gases in the combustionchamber whereby vaporization or superheating, or both, of the coolant isefl'ected, or the coolant may be delivered to a place of use withoutdirect contact with the gases. The tubular members forming the outercasing and the combustion chamber may be so constructed and arrangedthat the coolant flows through them separately, or in series, or inparallel, or in any combination of these types of flow.

It has been found entirely practicable to operate furnaces embodying theinvention at heat releases on the order of ten million B. t. u. per cu.ft. per hour, and evidence is available that far higher releases arewholly practicable. Moreover, these furnaces possess wide flexibility,so that this heat liberation rate can be varied almost instantaneouslythrough at least a ten to one range, for example, from one to tenmillion B. t. u. per cu. ft. per hour practically instantly. Withfurnaces embodying the invention and operating under constant firingconditions at the rates mentioned, it is possible to maintaintemperatures of the gases flowing from the furnace within i25 F. of agiven flgure, and to maintain CO2 percentages within 10.1%, with bothsubstantially uniformly distributed across the exit end of the furnace.It is possible with this uniformity to operate continuously with furnaceexit gas temperatures of at least 1800" F. The invention also permitsthe use of very high air preheats without jeopardizing the furnace orgas passages as evidenced by the fact that operations frequently havebeen conducted at air entrance temperatures of 600 F., and availabledata substantiate the fact that temperatures on the order of 1000 F. canbe sustained advantageously. For these reasons, high power can bedeveloped in furnaces of the invention which occupy no more than 2 or 3cubic feet.

Apparatus embodying the invention requires no firebrick or refractorylinings which customarily are employed in furnaces designed foroperation at high heat releases in order to sustain combustion throughthe maintenance of high temperatures and radiant heat effects. In placethereof, heat resistant metal or equivalent material is employed and iscooled by the secondary air supplied to the furnace and by other fluids.The metallic members are so constructed and arranged that they serve toshape the flame in the desired manner, to promote attainment of themaximum heat release, the maximum combustion speed, and the maximumhomogeneity of gases leaving the furnace, not only in regard totemperature but also with respect to constituents. This arrangement isparticularly advantageous where lightness of weight is required, and itavoids the erosion that may occur with flrebrick or refractory liningswith high velocities of air and gas, and which ordinarily results in theentrainment of particles which may have an abrasive action on turbineblading or cause deleterious results in portions of the system beyondthe combustion chamber. Moreover, the ejection of incandescent particlesof flrebrick or refractory would be disadvantageous with aircraftbecause of the resultant increase in the visibility of the aircraft. rvjI i The invention will be understood from the following descriptionwhen considered in connection with the accompanying drawings forming apart thereof, and in which: i

Fig. 1 is a longitudinal sectional view of a furnace embodying theinvention;

Fig. 1A, is front elevation partly in vertical cross section of theresilient means illustrated at 24' in Fig. 1

Fig. 2 is a transverse sectional view on line 2--2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1, showing another form of theinvention;

Fig. 4 is a transverse and elevation on line 44 of Fig. 3 after removalof inner and outer burner (front) plates with the burner and itssupporting plate omitted;

Fig. 5 is a longitudinal sectional view of a further form of theinvention having tubular members associated only with the means formingthe combustion chamber;

Fig. 6 is a transverse sectional view on line 6-6 of Fig.

Fig. 7 is a longitudinal sectional view of another form of the inventionhaving tubular members associated only with the outer casing of thefurnace, and

Fig. 8 is a sectional view on line 88 of Fig. '7.

Like characters of reference refer to the same or to similar partsthroughout the several views.

Referring to Figs. 1 and 2 of the drawings, the furnace shown has anouter casing having cylindrical end portions and II and a centralportion consisting of a tubular member l2 of spiral form having an inletl3 and an outlet I4. A corrugated Sylphonlike runner or strip I! ofspiral form fills the space between adjacent loops of the tubular memberl2 and is welded thereto. The terminal loops of the spiral tubularmember l2 are welded to the inner ends of the cylindrical peripheralportions of the end portions ill and II.

The combustion chamber I6 of the furnace is bounded by a tubular memberIf, preferably of resilient material, formed into a spiral with theindividual loops thereof disposed in spaced relation'ship, and a spiralmetallic band i8 which is secured to the tube I1. Fluid is introducedinto the spiral tubular member I! through an inlet I 9 and is dischargedthrough an outlet 20. As shown, the spiral band I8 is v-shaped intransverse cross-section, and the outer ends of the legs of the v arewelded to the tubular member If so that the apex of the v will extendtoward the outlet end of the furnace and the outer leg of the V will bespaced from the adjacent loop of the tubular member I1, therebyproviding a spiral passage 2| which connects the combustion chamber ISwith the annular passage 22 defined by the spiral tubular members l2 andI! and the metallic members secured thereto.

The terminal loop of the member I! at the inlet end of the combustionchamber abuts, or is secured to, an annulus 23 which is fixed to amember 24 having a plurality of radially extending arms 25' which arespaced from one another to form spaces 25" therebetween. The member 24is carried by, and movable longitudinally in, the end member ID inspaced relationship to the outer end 25 of the end member. The terminalloop of the spiral band l8 at the outlet end of the combustion chamber,is in engagement with, or is secured to, an annulus 26 which is fixed tothe outer end 21 of the end member ll. Expansion and contraction of thetubular member I1 is provided for by the movement of member 24 in theend member ID. Suitable resilient means'may be employed to urge member24 toward the tubular member I! and to permit outward movement of member24 upon expansion of the tubular member. One such means is shown in Fig.1A wherein cushioning cylinder 24 is mounted on housing In by means ofbracket 248 and cylinder plate 241 so that rod 242 of piston 243 engageschamber plate 24. Piston 243 travels in cylinder 24 in response to theurging of spring 244 or the rearward movement of plate 24. The tensionon spring 244 is adjusted by movement of disk 249 in response to handadjustment by knob 245 which causes threaded shaft 246 to travelinwardly or outwardly in plate 241. A plurality of cushioning cylinders24' are preferably installed at intervals around the peripheral portionof plate 24 as shown in Fig. 2.

A plurality of fuel burners 28 having louvers 29 arranged in spacedrelationship to each other and about the axis of the furnace, aresupported by the member 24. Air is supplied to the burners 28 through aconduit 30 which discharges into a chamber 3| in the end member It. Fromthe chamber 3|, the air flows through the burners and louvers and alsoflows through the openings in the outer peripheral portion of the member24 into the annular space 22 for flow through the spiral passage 2| intothe combustion chamber. The furnace is lighted off by any suitable meanssuch as the devices disclosed in our previously mentioned applicationSerial No. 479,010, filed March 13, 1943, issued March 21, 1950, asPatent No. 2,500,925.

The form of furnace shown in Figs. 1 and 2 is particularly well adaptedfor use in a gas turbine system, with the air compressor locatedadjacent the left hand end of the furnace as viewed in Fig. 1, and withthe gas turbine disposed adjacent the outlet end of the furnace at a theright hand end as viewed in Fig. 1. The turbine will drive a shaft 32which passes axially through the furnace and drives the air compressorand any other devices requiring mechanical power. Drive shaft 32 isprotected from the heat of the furnace by an outer metal shaft tube 33and by an inner metal shaft tube 33' between which is installed suitableinsulation 34. Any other suitable means may be employed for protectionof the shaft 32.

In operation, fuel is introduced into the combustion chamber through theburners 28, and primary air is supplied tov the burners from the chamber3| through the louvers 29. Secondary air is supplied to the periphery ofthe fuel and gas stream through the spiral opening 2| between thetubular member I! and the band it. The secondary air is directedobliquely into the combustion chamber with the result that the flame iscompressed and assumes a conical shape, combustion is completed quicklyand in a short path of flow of the fuel, the gases of combustion arediluted, a relatively high degree of homogeneity with respect to thetemperature and constituents of the gas mixture is obtained, and theheat release per unit volume reaches the high figures previouslymentioned. The coolant, which may be water, steam or chemicals, ispassed through the spiral tubular member l1 and cools the boundary ofthe combustion chamber including the bands l8, and is also passedthrough the spiral tubular member l2 and serves to cool the outer casingof the furnace.

With this arrangement, the combustion chamber is a cooled,spiral-air-foil surface with the tubular member I! forming the airentering edge and the V-shaped band IS the leaving edge, and the outercasing of the furnace is a continuous spiral accordion-like member alsocooled by the passage of suitable substances therethrough. The tubularmembers l2 and I! may be connected in parallel or in series to effectany desired result as far as the passage of coolant through the tubularmembers is concerned.

In the form of the invention shown in Figs. 3 and 4, the outer casingcomprises a tubular member 35 in spiral form with adjacent loops of thespiral spaced apart slightly in overlapping relationship. As shown, thetubular member is flattened to provide a streamlined or airv foilcross-sectional configuration withthe larger coils of the tubularmember. .chamber 31 is defined by a spiral tubular member 33 similar tothe member 35, with the loops spaced apart and in overlappingrelationship to provide a spiral passage 35 between adjacent loops. Inthe form disclosed, the inlet end of the member 38 is connected to theinlet end 45. Fig. 4, of the tubular member 35, and the outlet end isconnected to the outlet end 4| of member 35. With this arrangement, thecoolant, such as air, gas. water, steam or chemical, is passed inparallel through the tubular members 35 and 33. Airfor the furnace isdelivered through a suitable inlet to the chamber 42 and fiows therefrominto the annular passage 43 between the tubular members 35 and 35; Theinlet end of the furnace is closed by a circular plate 44 whichisisecured to the end loop of the tubular member 35, and the annularspace 43 at the outlet end of the furnace is closed by an annular plate45 which is attached to the loop at the other end of the member 35 andto the end loop of the member 33 at the outlet end of the furnace. Asingle fuel burner 45 is mounted on a disc 44' which is secured to theend of the tubular member 35 which burner fires the furnace through anopening in the disc. More than one burner may be employed if desired. Asshown, Jets 41 are disposed in those edges of the loops of the tubularmember 35 which are nearer the exis of the combustion chamber, throughwhich the coolant or other suitable substance may be discharged intodirect contact with the gases in the combustion chamber 31. These jetsmay be omitted if desired, or they may be disposed in certain loops andnot in others.

The operation of the form of the invention illustrated in Figs. 3 and 4is the same as that of Figs. 1 and 2 excepting when the jets 41 areemployed. With the jets 41 in some or all of the loops of the tubularmember 38, part at least of the coolant or other substance delivered tothe tubular members will be introduced into the combustion chamber 31into direct contact with the combustion gases, so that vaporization orsuperheating of the coolant or other substance will be effected.

The form of invention illustrated in Figs. and 6, has a cylindricalouter casing 55, and a combustion chamber 5| bounded in part by aplurality oi metallic bands 52, each of which has its annular wallsurface inclined inwardly toward the outlet end of the furnace, all ofthe bands being disposed in spaced relationship to the inner wall of thecasing and to each other, with the outlet end of each band except thelast, disposed within the inlet end of the next band in the direction offlow of the gases through the furnace. The first furnace band 52 at theburner end of the furnace has a cylindrical extension 53 which issecured to, or is in engagement with, the radially extending member 24.The inlet end of each band 52 is welded or otherwise secured to theinner peripheral portion of an annular tubular member 54, the interiorof which is connected to the interior of the adjacent member or members54 by a plurality of spaced, short tubular members 55 of smallerdiameter than the members 54 and which are curved outwardly, as shown,to take care of expansion readily. Coolant, such as water, gas, steam orchemical, is introduced into the members 54 through an inlet connection55 and is withdrawn through an outlet connection 51.

The operation of the embodiment shown in Figs. 5 and 6 is substantiallythe same as the embodiments previously described, excepting that theouter casing 50 is cooled only by ambient air.

The arrangement shown in Figs. 7 and 8 is like the form shown in Figs. 5and 6, excepting that the outer casing is formed principally of tubularmembers and the metallic bands forming the casing do not have tubularmembers associated with them. Referring to Figs. 7 and 8, the outercasing comprises a plurality of straight tubular members 50 extendingparallel to the axis of the combustion chamber 5| and arranged in acircle with adjacent members in contact with each other, as shown inFig. 8. Leakage between the tubes is prevented by means of a cylindricalplate 5| welded, or otherwise secured, to the members 50. The metallicbands 52 surrounding the combustion chamber, are in spaced relationshipto the tubular members 50 to provide an annular space 62 through whichsecondary air fiows from the chamber 3| to the combustion chamber 5|through the spaces between the bands 52, as previously described. Asshown, the ends of the tubular members 55 at the burner end of thefurnace are in communication with the chamber 3|. so that air from thechamber 3| will enter each of the tubular members 60. The members 50 areconstructed to supply air or other coolant to all of the annular spacesbetween the bands 52, or only to such spaces as may be desired. Asillustrated, each tubular member 50 is provided with a slot 53, andabaflle member 54 within the tubular member and so positioned withrespect to the slot 53 that air or other coolant is directed into thedesired space between the bands 52. Air also will enter the tubularmembers 50 through the slots 53 from the annular space 62 and will flllthe members 60 from the baflle members to the ends of the members at theoutlet end of the furnace. With this arrangement, the coolant can beintroduced into a region of the combustion chamber adjacent the outletend thereof in a relatively cool condition because the coolant will notbecome highly heated in flowing through the tubular members 50., If itis desired to utilize a coolant other than air, such as steam, gas,water or a chemical, the inlet ends of the tubular members 50 may beconnected to a suitable manifold to which such other coolant would besupplied.

From this description, the operation of the form of furnace shown inFigs. 7 and 8 will be apparent and will be substantially the same as theoperation of the forms shown in Figs. 1 to 6.

The relative quantities of secondary air introduced between adjacentbands is dependent upon the angle, length and general configuration ofthe bands, and the flow area of the openings between bands. Preferably,the bands and the air passages between them are so proportioned thatcombustion is completed in the earliest practicable time and in theminimum length of furnace, irrespective of high velocities of air, fuel,or both, and so that maximum homogeneity of the gas mixture and maximumprogressive heat releases are obtained prior to the passage of themixture beyond the end of the last band.

Preferably, the furnace bands are made of high temperature resistantalloy, such for example, as an alloy having 25% chromium and 20% nickel,or an alloy having 60% cobalt, 30% chromium, and 10% molybdenum. Thefurnace outer casing,

including any tubular members therein, may be of suitable metal having alower percentage of constituents providing high heat resistance whichmay require none of these alloying materials, but is constructedsufliciently heavily to withstand any pressure of the air deliveredthrough them by a. compressor or other means.

Any suitable conbustible may be used for fuel for firing the furnacesuch as oil, pulverized coal, gasoline or gas.

Should the cooling of the furnace bands and casing and the related partspresent any difflculty, such as may occur with high preheat or withrecycling, it may be desirable to employ firing devices for the furnace,or combustibles, or both, which are capable of producing blue flames,thus minimizing radiation, particularly in the initial stages ofcombustion near the firing end of the furnace. If desired, the furnacebands whether cooled by air or any suitable fluid, may be plated withsuitable metals such as cobalt, rhodium, ruthenium, or the like, andthese plated surfaces may be polished on the inner or furnace sides toprovide reflecting areas. Liners of similar materials may be employed inthe event plating is impractical. By the use of such means, heatabsorption of the furnace bands, casings and associated parts may bedecreased materially.

The invention disclosed herein may be manufactured and used by or forthe Government of the United States for Government purposes without thepayment of any royalty thereon or therefor.

It will be understood that changes may be made in the form, location andrelative arrangement of the several parts of the furnaces disclosedherein, and changes may be made in the steps or in the sequence of stepsof the method disclosed. without departing from the principles of theinvention. Accordingly, the invention is not to be limited excepting bythe scope of the appended claims.

What is claimed is:

1. Apparatus for the combustion of fuel comprising means forming acasing, means within the casing forming a combustion chamber and spacedfrom the inner wall of the casing, means for projecting fuel and primaryair into the chamber wherein the fuel is ignited and burns in a movingstream therein, the means forming the combustion chamber beingconstructed and arranged to provide an opening adjacent the burning fuelstream, means for supplying air to the space between the casing and thechamber for passage through said opening into the cha m' ber, the meansforming the combustion chamber comprising a tubular member of spiralform with the loops thereof spaced apart, a spiral member V-shaped intransverse cross-sectional configuration having the ends of the legsthereof fixed to the tubular member in such manner that one leg extendsbetween adjacent loops in spaced relationship to one of said adjacentloops and the other leg extends substantially longitudinally of thecombustion chamber, and means for supplying a coolant to said tubularmember.

2. Apparatus for producing high speeds of combustion of fuel and highheat releases therefrom; comprising in combination: an outer casing;means forming an elongated unobstructed combustion chamber positionedwithin said casing to provide an elongated annular space therebetween;an outer spiral tubular coil in said casing extending adjacent saidspace; inlet and out- 8 let means for circulating 'coolant through theinterior of said coil; means for the high speed projection of fuel andprimary air into said chamber wherein said fuel is ignited and burnstherein in a stream; means for projecting secondary air into said space;said means forming said chamber comprising a spiral deflecting bandsurrounding said chamber and arranged to provide a spiral openingextending along said chamber adjacent said stream whereby said secondaryair is deflected inwardly and forwardly in an oblique direction tocompress said stream; an inner spiral tubular coil surrounding saidchamber and positioned adjacent said spiral opening; and inlet andoutlet means for circulating coolant through the interior of said innercoil.

3. The combination of claim 2 wherein said chamber includes a rearwardlydisposed end plate mounted for limited longitudinal movement within saidcasing, and adapted to retain the rearward end of said band and saidinner coil; resilient means mounted in cooperating relationship withsaid plate whereby said plate may be moved rearwardly by longitudinalexpansion of said band and said inner coil and moved forwardly by saidresilient means upon longitudinal retraction of said band and said innercoil.

4. Apparatus for the combustion of fuel including a casing comprisingatubular member of spiral form with the loops thereof spaced apart and aspiral strip welded to the tubular member for closing the space betweenthe loops, means within the casing forming a combustion chamber andspaced from the casing, said means comprising a tubular member of spiralform with the loops thereof spaced apart, a spiral member V-shaped intransverse cross-sectional configuration having the ends of the legsthereof fixed to the tubular member so that one leg extends betweenadjacent loops in spaced relationship to one of said adjacent loops andthe other leg extends substantially longitudinally of the combustionchamber, the point of the V being directed towards the discharge end ofthe chamber, means for supplying a coolant to said tubular members,means for projecting fuel and primary air into the combustion chamberwherein the fuel is ignited and burns in a moving stream therein, andmeans for supplying air to the space between the casing and the chamberfor passage into the chamber between the loops of the tubular memberforming the chamber.

CLAUDE A. BONVILLIAN.

RALPH C. BRIERLY.

SAMUEL LETVIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,372,121 Davis Mar. 22, 19211,483,917 Tucker Feb. 19, 1924 1,531,475 Brandt Mar. 31, 1925 1,817,470Adams Aug. 4, 1931 1,828,784 Perrin Oct. 27, 1931 2,268,464 Seippel Dec.30, 1941 FOREIGN PATENTS Number Country 4 Date 127,287 Germany Jan. 9,1902 368,263 Great Britain Feb. 26, 1932 376,974 Great Britain July 21,1932

